With songwriters like John Lennon, Paul McCartney, and George Harrison (and even Ringo Starr now and then), The Beatles didn't need to reach out for the material of others very often. When they did, their musical chemistry and gleaming vocal harmonies tended to transform those songs, even those that were done by iconic artists. The Beatles pretty much stopped with the cover songs after 1965. What they left behind on their official releases gives us a pretty wide range of covers from which to rank the five very best.